Synchronizing and phasing system



G. V. NOLDE SYNCHRONIZING AND PHASING SYSTEM Filed May 5, 1943 4 SheetsSheet l IN V EN TOR.

July 31, 1945. G NOLDE 2,380,542

SYNCHRONIZING AND PHASING SYSTEM Filed May 5, 1943 4 Sheets-Sheet 3 MOTOR SWITCH BOX 751s ms 09 Fll3 E INVENTOR.

' a By Z060 y 31', 1945- G. v. NOLDE ,380,

SYNCHRONIZING AND PHASING SYSTEM Filed May 5, 1945 4 Sheets-Sheet 4 MOTOR IEIE-B- IN V EN TOR.

Earented July 31, 5

George ,v. Noldc, Berkeley, Calif.

- Application May 5, 1943, Serial No. 485,732

8 Claims.

1943, of which this application is a continuationin-part. It should be understood, however, that although described in connection with a navigational guide system, the method and apparatus disclosed hereinafter may beutilized to synchronize two or more remotely separated cyclic mechanisms of any kind, with respect to speed and cyclic phase of operation.

The present invention represents a development and improvement of an early system used by Hughes in 1855-1863 to synchronize and phase rotating mechanisms or a. telegraph printer well known in the art and described in many publications such as, Harrison, Printing Telegraph Systems and Mechanism, Langman Green and (20., London, 1923, pages 35 to 37. The Hughes system was based on intermittently connecting two remotely separated rotary printing wheels to two separate respective motors by two individual.

clutches. The two printing wheels were driven through a single revolution and stopped at a given phase of rotation. Preliminary printing signalswere transmitted from one station to another at certain prescribed intervals to enable the operator at the receiving station to synchroniz his motor with that of the transmitting station. After the motors were thus synchronized the two printing wheels continued to rotate intermittently and the printing signals served tocorrect the phase of these printing wheels during printing operation proper.

It will be seen from the following detailed description that the present invention represents an improvement of this a fully automatic but relatively simple synchrohiring and phasing system as compared with the elaborate modern systems provided for this purpose.

It is a principal object of the invention therefore to provide automatic and positive means for effecting and controlling a continuous and noninterrupted synchronization and phasing of two remotely separated devices. 7

It is a further object to provide simultaneous phasing of two or more synchronously operable devices. A

It is a further object of this invention to provide an improved clutch specifically adapted to basic system and provides cooperate with alternating current synchronous motors.

It-is a further object to provide a positively limited friction slipp mechanism between the driving and driven components of a transmission.

It is a further object to provide a. friction slipping mechanism between the driving and driven components of a transmission which will allow the driven component to lag behind the driving component by a predetermined fixed amount.

It is a further object of this invention to provide a phasing system in which a communication chan nel used for phasing at the beg g of operation is freed thereaftenfor other signal uses without disrupting phasing.

Other more specific objects will appear during the following description of a preferred form oi! the invention, reference being had to the accompanying drawing, forming a part of this specification in which:

Fig. 1 is a side elevation 01' the motor and clutch units of the preferred embodiment oi the present invention. 7

Fig. 2 is a sectional view taken on the line 2-2 of Fig. 1, showing the internal mechanism of the clutch.

Fig. 3 is a sectional view taken on the line 3-3 pawl to the casing of the clutch.

Fig. 4 is a wiring diagram oi the apparatus situated at one location such as aboard an aircraft.

Fig. 5 is a wiring diagram of the apparatus situated at another location such as at a point on the ground.

Fig. 6 is a side elevation of the motor and clutch t of the modified embodiment showing paricularly the slip mechanism between the motor and the clutch.

Fig. 7 is an enlarged view 0! the spring Pressure element of the slip unit. 7

Fig. 8 is a wiring diagram of the modified embodiment showing particularly the control circuit for the motor, clutch, and slip unit.

Indexed clutches and control mechanism therefor the frequency of the same source by means including a transformer transmitter, receiver, filter, or by any equivalent communication channel.

A clutch is interposed between each motor and the instrument for which it is used. These clutches must be of the kind in which the driven part of each clutch is fixed in a definite angular position relative to the frame of the apparatus when the clutch is disengaged.

The clutches of this general type are widely used in calculating machines, teletypes, et cetera and this type of clutch will be referred to hereinafter as an indexed clutch.

The indexed clutches used in the present preferred embodiment are engaged by respective electromagnets which are in a common circuit or are'controlled through a common communication channel also including transmitting and receiving devices. Simultaneous engagement of the clutches thus causes their respective instruments to rotate at synchronous speeds and in synchronous phases of operation.

The synchronous motor 55 (Fig. 1) which is shown as being for the instrument on board the aircraft, corresponds to the motor of the same number shown in Fig. 4 of the aforementioned Nolde Patent Number 2,321,698. This motor is selectively connected and disconnected to and from the instrument drive shaft I20a by an indexed clutch 50 which may be of the well known ratchet type.

In the particular embodiment shown the ratchet I (Fig. 2) has four teeth for reasons set forth hereinafter. This ratchet is fixed t0 and rotates with the motor shaft I202). A clutch casing I (Figs. 2 and 3) is freely mounted on the shaft I?) and is fixed to the shaft Ilia. The casing carries a stud I05 upon which is pivoted a clutch pawl I01 having a tooth I 00 adapted to move into engagement with the ratchet I00, A spring urges the pawl clockwise about stud I05 but when the clutch is disengaged, as shown in Fig. 2. such clockwise movement is prevented by a. pin III blocking a tip IIO of the pawl. Removal of the pin III from against the tip IIO by mechanism described immediately hereinafter allows the spring I09 to rock the pawl into engagement with the rotatingratchet whereby the whole clutch as a unit rotates with the ratchet and shaft I20!) and thus drives the instrument shaft I20a at the same speed as the motor shaft I20b..

The above described clutch engagement is controlled by an electromagnet 55 (Fig. 1) and related mechanism which includes a conical member 58 which is fixed to the magnet armature and slidable thereby in the bearing H5 in the frame I I5 of the apparatus. A pin 55 is journaled in the frame. The right end of this pin engages the member 59 and the left end thereof engages an arm I which is integral with a shaft I 00 journaled in a bracket or part I25 of the frame II5 (Fig. 1). This shaft carries two arms I21 and I25 which are connected at their outer ends by a square shaftIIS, thereby forming a rigid bail comprising the two arms I21 and I28 and the two shafts I29 and I30 all rockable about the center of shaft I30. The upper arm I21 carries an extension which carries the aforementioned pin II I. A spring III is compressed between a lug on the frame and a lug on the extension Ill and urges the entire assembly counterclockwise about the center of shaft I 50 and thus normally holds the pin III in the clutch disengaging position shown in Fig. 2. Energizaftion of th magnet 55 moves the member 55 upwardly, whereupon the tapered surface of the latter cams the pin 58 toward the left, as viewed in Figs. 1 and 2, which rocks the arm I25 and shaft I30 clockwise and moves the pin III out of the notch in the casing of the clutch to release the pawl I01 and cause engagement of the clutch as described hereinbefore.

Control circuits The electric motor (Fig. 5) which corresponds to the motor of the same number in Fig. 8 of the aforementioned Nolde patent is connected to a source I50 of alternating current by leads |5I and I52, the latter passing through the transformer 83, This motor is of the well known synchronous type and is therefore driven at a constant speed in synchronism with the frequency of the current source I50.

A transmitter", corresponding to the transmitter of the same number in said Nolde patent. is controlled by the secondary winding of the transformer 81 so as to transmit a carrier wave which is modulated by the alternating current of the current source I50. The signal so transmitted is received by a receiver I5 (Fig. 4) which, through a filter, supplies the alternating current of the same frequency as generatedby the source I50. thereby causing the motor 55 to rotate in synchronism with the motor 55.

A transmitter 15 (Fig. 4) and receiver I1 (Fig. 5) are also provided and tuned with respect to each other. and when the operator at the receiving station wishes to start operation of an apparatus such as disclosed in said Nolde patent he closes the switches including contacts I and I45 (Fig. 4) after having tuned his receiver I5 to the transmitter 14. Closure of the contacts I48 closes the circuit from the battery I55 to the electromagnet 55 described hereinbefore in connection with Fig. 1 which actuates the armature.

its cone 5! and pin 58 to cause engagement of the clutch 60. Simultaneous closure of contacts I46 connects the transmitter 75 to the antenna I51 and emits a signal of a prescribed frequency. different from that emitted by the transmitter ll, to an antenna I59 and the receiver 11. An electromagnet is energized by the receiver 11 and closes a switch I" which closes a circuit between 9. battery I50 and an electromagnet l1 corresponding to the magnet of the same number in said Nolde patent.

By means of this arrangement, the cone 55 causes engagement of the clutch 54 within a small fraction of a second of the time the cone 5S causes engagement of the clutch 50. It may be observed that with the above described arrangement of the basic parts of such phasing and synchronizing system, any clutch construction may be used, provided both clutches require the same time for engagement and are of the above explained indexed starting type. For cooperation with alternating current synchronous motors. however. certain characteristics of such motors may be used to an advantage in combination with some improved specific features of the clutches. as will be seen from the following description thereof.

In this preferred embodiment the motors 55 and 35.(Figs. 4 and 5) are four pole motors and the ratchets of the clutches 50 and II each have four teeth. and therefore, the angular positions of the clutch ratchets are the same at the same instant and simultaneous engagement of the two clutches 50 and U will cause the ratchets to drive their housings and respective shafts I20 and H011 from the same starting position at the same time by the corresponding ratchet tooth of each clutch ratchet. In this way the shafts I20a and I20 are driven at a synchronous speed and in exact phase relation as well, even if the times of operations of the magnets 55 and 41 (Figs. 4 and 5) are slightly different. The number of teeth of the clutch ratchets. do not have to be the same as the number of poles of the motors but according to this preferred embodiment may be even multiples thereof such as 4, 8, or 12 teeth fora four pole motor, or 2, 4, 6, 8, etc., for a two pole motor. It is easily understood by those skillful in the art that channels of communication including transmitter 14 and receiver '15 which serves to transmit a synchronizing frequency and the second communication channel including transmitter 18 and receiver 11 which is used to transmit a phasing impulse, may be of any other type besides that described inconnection with Figs. 4 and 5 of the present case. For example, a single carrier wave may be used to transmit two modulating frequencies of which one may be used for driving the motors at a synchronous speed and the other for phasing the clutches. Two separate wire lines could be used as well, or any other equivalent means known in the art under the term communication channels may be substituted therefor.

Modified embodiment I If the phasing mechanism described above were used to drive a mechanism which had an excessive amount of inertia, the initial load caused by such an instantaneous start as would result from clutch engagement might cause the motor to lose one or more phases of its cycle before the driven part of the apparatus is brought up to the synchronous speed. If this loss of phases were not the same at both stations the system would be out of phase and would therefore not operate correctly, therefore a slipping mechanism may be provided in accordance with the modified embodiment whereby the driven part of the apparatus may initially lag behind the synchronous speed of the motor at each station by a predetermined fixed amount before getting up to speed. This lag could be made any amount from one revolution of motor or ten or twenty revolutions thereof, but in any one case the amounts of slippage 0r lag must be the same or even multiples of full revolutions for both stations. In the modified embodiment the slippage mechanism permits the clutch and driven part of the apparatus to drop behind the motor by three full revolutions during the acceleration of the clutch following engagement thereof, and after the three revolution displacements to establish a positive driving connection between the motor and clutch.

The motor shaft I (Fig. 6) carries integrally therewith a fly wheel IN to add to the inertia and momentum of the rotating part of the motor.

The shaft I10 also has threads I12 on which is threaded a disc I15. The threads on the disc are made to fit the shaft threads with considerable friction and the disc itself is split at I16, as shown in Fig. '7, to permit the disc to spread and prevent binding between the shaft and disc. Preferably the threads on the shaft are slightly larger at the lower end so that the friction between the shaft and disc will increase as the disc is moved downwardly by means described immediately hereinafter.

A friction disc I18 is freely mounted on the shaft I10, and supported on that shaft between th collars I10a and I10b which are pinnedor otherwise fixed to the shaft I10. A disc I10 is freely mounted on shaft I10 and isfixed to a coaxial shaft I8I. Each of the three discs I18, I18 and I18 has two holes into which are fitted two pins I and I88 as shown in Fig. 7. The two pins are fixed to the discs I18 and I18 and are slidable in the holes in disc I15 to permit the latter to slide up and down on the pins.

The clutch 60a is of the same construction as clutch 80 described hereinbefore in connection with Fig. 1 and is caused to engage by energization of the magnet 55a and the resulting upward movement of the tapered member 88a in exactly the same way as described hereinbefore.

Before the clutch is engaged, the motor 56a is started by the mechanism shown diagrammatically in'Figs. 4 and 5 and described hereinbefore.

The clutch ratchet is fixed to shaft I8I (Fig. 6) and is driven by the motor by the above described disc assembly. Since there is a relatively light load required to drive the clutch ratchet idly, the friction between the shaft threads and the threads in disc I15 is sufficient to drive the two discs I18 and I19 and the shaft I8I without slipping. When the clutch is engaged, however, the load is instantaneously increased and tends to retard the disc assembly while the motor speed is maintained, in which event the disc I15 slips on the threads I12 and moves downwardly to the position shown by dotted lines and identified as So. When the disc I15 reaches the position shown by dotted lines and identified by the reference numeral "So, it abuts the collar I18?) and is positively stopped, thereby forming a solid and direct connection between the motor shaft I10 and the clutch ratchet shaft I8I. The ratchet shaft is thus allowed to drop three full revolutions (in this particular embodiment) behind the motor during the downward travel of the disc I15.

Means must be provided to return the disc I15 to the position shown, therefore, the operation described above is preceded y the following preparatory operation. From the above description it may be seen that during the driving operation of the mechanism the disc is in its lowered position H511 and when the machine is stopped the disc remains in this position. During the above mentioned preparatory operation, before the clutch is engaged, the motor is driven backward. At this same time, an lectromagnet I is energized which ejects its armature I86 and presses ,a friction pad I81 against the disc I18 with sufficient force to overcome the friction between the threads I12 of the shaft and those in the disc I15. The disc I15 is thus driven backwards or upwardly to the position shown. The magnet IBG is then deenergized and the motor is reversed and driven forward by means described hereinafter, after which the clutch is engaged and the operation is effected to drive the disc I15 down to its driving position I15a as described hereinbefore.

Alternative wiringdiagram 2", through a second coil 2I I, lead 2|2 through th primary winding 2I2 of a transformer 222, lead 2 to ground. The primary winding 222 of a transformer 224 is also energized by closure of the circuit including lead 229.

Closure of switch 222 also closes a parallel circuit through the synchronous motor 56a (Fig. 8) and a second parallel circuit through a second motor 56b. The first circuit includes lead 2I5, the closed switch 2 I6, lead 2 I 1, through the starting winding of the motor 56a, lead 2I6 and condenser 2I9, the contacts 220, lead Hi to ground. The second circuit which leads through the starting winding of motor 56b includes the identical arrangement including leads 225, 226, 221, and 222 to ground. The main winding of the motors 52a is energized by a branch circuit including leads 220 and 22 I, and their respective closed contacts 222 and 232, while the main winding of motor 56b is similarly energized by leads 224 and 225. With the switches arranged as shown in Fig. 8, the fields of the starting windings of the two motors are such that the motors are driven backwards for reasons described hereinbefore in connection with Fig. 6. Also as described before the brake magnet I25 is energized during the preparatory operation and this is effected by the circuit including lead 2I5, described above, and lead 221 through the magnet I65, corresponding to the magnet of the same number in Fig. 6, lead 222, switch 22!, lead 22I to ground. The break magnet I25a for the remote station is similarly energized by a circuit including leads 240 and 24I.

In accordance with the description of Fig. 6 the backward rotation of the motor and energization of the break magnet I65 drives the disc upwardly to the position shown. During the short interval of time required to do this, the coils 201 and 2 (Fig. 8) which are heated coils, heat up their respective bi-metal strips 242 and 24.4 which move two respective insulation rods 245 and 246 toward the left as viewed in Fig. 8. The leftward movement of rod 246 opens the switch 229 and causes deenergization of the magnet I85 and leftward movement of rod 246 similarly causes deenergization of magnet l65a. Rod 245 also actuates the motor switches so as to open the contacts 2", 222, 222. and 220 and to close the opposing contacts. This reverses the current through the starting windings of motor 561: and temporarily opens and then closes the circuit through the main winding in accordance with the conventional way of reversing a synchronous motor. The rod 242 similarly reverses the motor 52b so that both motors run idly in a forward direction.

All the foregoing operations take only one or two seconds. and so, shortly after closure of switch 222 the operator closes a switch 256 and releases the same which immediately opens again. During the time the latter switch is closed it closes a circuit through the clutch engaging magnet 25a so as to effect engagement of the clutch 200 (Fig. 6). This circuit includes lead 255, connected to a direct current supply unit 256, leads 251, and 252, the normally closed contacts 255. through the clutch magnet 55a, and lead 262 to ground. The clutch magnet 55b for the clutch at the remote station is also energized by closure of switch 256 which closes a circuit including lead 251, the communication channel 265, lead 266, the normally closed contacts 261, through the magnet 55b, lead 268to ground.

By means of the foregoing arrangement, therefore, the motors at both stations are driven backwards during the preparatory operation and the break magnets are energized to drive the disc I15 (Fig. 6) at each station upwardly. Then the break magnets are deenergized and the motors are driven forwardly, immediately after which the clutch magnets a and 55b are energized to cause simultaneous engagement of their respective clutches.

Upon such clutch engagement the driven shafts rotate in synchronism and phase and remain in synchronism and phase so long as the clutch magnets are maintained energized. Means are provided to maintain such energization by means of a circuit individual to each station so that communication channel 265 may be freed for other communication. This means is automatically effective immediately upon the initial energization of the clutch engagement magnets as follows. When the cone 69a (Fig. 6) is moved upwardly, as described hereinbefore, to cause engagement of the clutch a a collar 210 engages a tip 2'" of a lever 212 and rocks the same clockwise about its pivot 213. The lever 212 has an insulation tip 214 which is adapted, upon such clockwise rocking of lever 212, to close a pair of switch contacts 21.5. An insulation lu 216 is secured to one of the leaves of the latter switch and engages a leaf of the adjacent switch 259 as shown so that following closure of the first switch the lug 216 opens the switch 259 in a manner customary in make before brea switching arrangements.

The switch 259 at the control station and its corresponding switch 261 at the remote station were described hereinbefore in Fig. 8 as in the circuit which causes initial en'ergizaticn of their respective clutch engaging magnets 55a and 55b. Before these switches are opened, however, the switch 215 is closed as described above, together with the corresponding switch 211 at the remote station and each thus closes a holding circuit through its respective magnet. The closure of switch 215 closes the circuit including lead 222 connected at one end to the D. C. power supply unit 256 and at its other end to one side of the switch 215. The other side of the switch is connected to th magnet 55a which is in turn connected to ground by lead 262. Closure of switch 211 (Fig. 8) at the remote station similarly closes a circuit including lead 28I, connected at its upper end to a D. C. power supply unit 222, and at its lower end to one side of the switch 211, the other side of which is connected to the magnet 551:, connected to ground by lead 262. Each magnet is thus maintained energized by means of a circuit and power supply at its own station so that opening of the switches 259 and 261 are ineffective to deenergize the respective magnets.

As described hereinbefore switch 250 is closed by the operator at the control station and then is released to open, and during the short interval of time the latter switch is closed the magnets .are energized and their holding circuits are closed so that thereafter the communication channel 265 may be freed for other uses.

The clutches may be disengaged and the entire system including operation of the motors may be stopped simply by opening the switch 220 which opens the circuits through the transformer 222 for the power supply unit 256, the circuit through the motor 56a and the heater coil 221 and through the communication channel 209, the circuit' through the heater coil 2 and the transformer for the power unit 222 and also the circuits through the motor 56b. Deenergization of the two power units causes deenergization of the clutch magnets 55a and 55b and disengagement or their respective clutches to thereby bring the system to a condition of rest.

The scope of this invention should not be restricted to the preferred embodiment or modifications described hereinbefore except as limited by the prior art, for example, the ratchet indexed clutches could be replaced by spiral jaw indexed clutches, or any other equivalent construction. The maintenance of engagement of the clutches by the holding circuits disclosed hereinbefore could as well be efiectedby a mechanical latch: while the solenoids and cone shaped armatures may be replaced by any other well known clutch engaging mechanism. The scope of my invention is described in the following claims.

I claim:

1. A remote control system for synchronizing the phase of rotation of a first device with respect to the phase of. rotation of a second device. comprising; a first motor operable to rotate said first device, a second motor operable to rotate said second device, a first clutch between said first motor and said first device. a second clutch between said second motor and said second device, a source of electrical energy, a first communication channel between said source and said two motors for transmitting said energy from said source to said motors to thereby drive said motors at equal speeds, a first electrically controlled means for engaging said first clutch, and a second electrically controlled means for engaging said second clutch, a second communication channel between said first and second clutch engaging means, and means for enabling said second communication channel to simultaneously operate said first and second clutch engaging means.

2. A system for synchronizing and phasing two rotating members having a motor operable to rotate the first one of said two members, a second motor operable to rotate the second one of said two members, a first clutch between said first motor and said first member, a second clutch between said second motor and said second member, a first electrically controlled means for engaging said first clutch, and a second electrically controlled means for engaging said second clutch; in combination with a first communication channel for controlling said motors to rotate at equal speeds, a second communication channel between said first and said second clutch engaging means, and means for enabling said second communication channel to cause simultaneous operation of said first and second clutch engaging means.

3. In a system for synchronizing and phasing a first rotatable member and a second rotatable member, a first alternating current synchronous motor having a predetermined number of poles and operable to rotate said first member, a second alternating current synchronous motor having the same predetermined number of poles and operable to rotate said second member; in combination with two clutches each including an engagement member having a plurality of engagement elements thereon which are equal in number to the number of poles of said motors, the first of said two clutches being interposed between said first motor and said first member, and the second of said two clutches being interposed between said second motor and said second member, and means operable to cause simultaneous engagement of said two clutches.

4. In a system for synchronizing and phasing a first rotatable member and a second rotatable member, a first alternating current synchronous motor having a predetermined number of poles and operable to rotate said first member, a second alternating current synchronous motor having the same predetermined number of poles and operable to rotate saidv second member; in combination with, two clutches each including a en-' gagement member having a plurality of engagement elements thereon which are equal in number to even multiples of the number of poles of said motors, the first of said two clutches being interposed between said first motor and said first member, and the second of said two clutches being interposed between said second motor and said second member, and means operable to cause simultaneous engagement of said two clutches.

5. In a system for synchronizing and phasing a first rotatable member and a second rotatable member, a first motor operable to rotate said first member, a second motor operable to rotate said second member, and means for controlling said motors to rotate at equal speeds; in combination with two coupling devices each one interposed between its respective motor and rotatable member, said coupling devices including means for causing a predetermined amount of slippage between the motor and its corresponding rotatable member.

6. In a system for synchronizing and phasing a first rotatable member and a second rotatable member, a first motor operable to rotate said first member, and a second motor operable to rotate said second member; a coupling device interposed between one of said motors and its corresponding rotatable member, said coupling device including a friction clutch having a driving mem ber and a driven member, said driving member having a helically threaded portion and said driven member having an element for engagement or said threaded portion.

'7. A system for synchronizing and phasing two rotating members having a motor operable to rotate the first one of said two members, a second motor operable to rotate the second one or said two members, a, first clutch between said first motor and said first member, a second clutch between said second motor and said second member, a first electrically controlled means for engaging said first clutch, and a second electrically controlled means for engaging said second clutch; in combination with, means for controlling said two motors to rotate at equal speeds, a communication channel between said first and said second clutch engaging means, means for enabling said communication channel to cause simultaneous operation of said first and second clutch engaging means, and means for holding said two clutches in engagement independently of the control exercised by said communication channel.

8. In a system for synchronizing and phasing two rotating members, a motor operable to rotate the first of said two members, a second motor operable to rotate the second one of said two members, a first clutch between the first motor and said first member, and a second clutch between said second motor and said second member; in combination with a communication channel for controlling said two motors to rotate at equal speeds, and means for causing simultaneous engagement of said two clutches.

GEORGE V. NOLDE. 

